full-stack_overview.md

Full-Stack Overview

This is an overview of the app as a whole.

Contents:

• Existing Features
• Technologies
  • MongoDB
  • Express
  • React
  • NodeJS
• Architecture

Existing Features

It's already possible for a user to:

• Sign up
• Sign in
• Sign out
• View a list of posts

Technologies

Here's an overview of the technologies used to build this template application. You don't need to do a deep dive on each one right now. Instead, try to get a feeling for the big picture and then dive into the details when a specific task pushes you in that direction.

M is for MongoDB

MongoDB is a NoSQL database program that stores data in collections of documents (in a format similar to JSON), rather than in tables. The application interacts with MongoDB using a tool called Mongoose.

E is for Express

Express is a Javascript equivalent of Flask (Python) or Sinatra (Ruby). The structure of this application will feel quite different to what you're used to but the principles are the same.

R is for React

React is a hugely popular tool that is used to build engaging front ends. The basic principle is that the front end is split up into components, each of which could include some logic, template structure (HTML) and styling (CSS).

N is for Node

JavaScript was originally designed to run exclusively in browsers, such as Chrome. Node is a tool that allows you to run Javascript outside the browser and its invention made it possible to build full stack Javascript apps.

We also used...

• Vite to generate our React Project
• Vitest for unit testing on the frontend
• Jest for unit testing on the backend
• Mongoose to model objects in MongoDB
• ESLint for linting
• Nodemon to reload the server automatically

Architecture

This application is comprised of two distinct pieces:

• A backend API built with Express
• A frontend built with React

It's important to note that these are two completely different programs. They don't share any code. They have their own package.json files and dependencies. Imagine that they're always running on two different machines (though when you are working locally, everything is running on your computer).

The only way the frontend can communicate with the API is through HTTP requests over the network. The React front end sends HTTP requests to the backend API and receives JSON responses, instead of a whole page of HTML.

For example, the React front end would send this request to retrieve the entire Post collection.

GET "<BACKEND_URL_HERE>/posts"

And the body of the response would look like this.

{
    "posts": [
        {
            "_id": "62f8ef0e6c1ffcf74cbbb181",
            "message": "Hello, this is my first Acebook post!",
            "__v": 0
        },
        {
            "_id": "62f8ef366c1ffcf74cbbb188",
            "message": "Welcome to Acebook! Have an Acetime :)",
            "__v": 0
        },
        {
            "_id": "62f8f08af1cffef85a7426ae",
            "message": "Thank you :D",
            "__v": 0
        }
    ]
}

Here's a diagram of the above

Once received by the React FE, the JSON in the response body is used to render a list of posts on the page.

This architectural pattern is has a number of advantages. For example, it allows teams to build multiple front ends, all of which use the same backend API. You could, for example, go on to build a mobile app without needing to create another backend API.